ISSUE-18506: [Doc] Improve Pulsar Pub/Sub Throttling Doc

[sijie]

Original Issue: apache#18506

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What issue do you find in Pulsar docs?

The current documentation about Pulsar message pub/sub throttling is insufficient.

What is your suggestion?

• Have a central page about Pulsar message throttling.
• Explain the goal of Pulsar message throttling.
• Explain how and where Pulsar throttling works.
• Explain what configs and admin APIs are available to set throttling.
• Explain how throttling broker configs and admin APIs are working together if they are configured at the same time. (explain config-adminAPI compatibility)
• Explain how throttling works with different features: message batching, compression, chunking, backlog, non-durable topics, partitions, replicas, entry filter, flink, sink/source, functions, offload and etc. (explain feature compatibility)
• Explain how throttling can be monitored
• Give example setups for best throttling practices

Any reference?

https://pulsar.apache.org/docs/2.10.x/admin-api-namespaces/#configure-dispatch-throttling-for-topics

pulsar % grep Throttling conf/broker.conf
topicPublisherThrottlingTickTimeMillis=10
brokerPublisherThrottlingTickTimeMillis=50
brokerPublisherThrottlingMaxMessageRate=0
brokerPublisherThrottlingMaxByteRate=0
subscribeThrottlingRatePerConsumer=0
dispatchThrottlingRateInMsg=0
dispatchThrottlingRateInByte=0
dispatchThrottlingRatePerTopicInMsg=0
dispatchThrottlingRatePerTopicInByte=0
dispatchThrottlingOnBatchMessageEnabled=false
dispatchThrottlingRatePerSubscriptionInMsg=0
dispatchThrottlingRatePerSubscriptionInByte=0
dispatchThrottlingRatePerReplicatorInMsg=0
dispatchThrottlingRatePerReplicatorInByte=0
dispatchThrottlingRateRelativeToPublishRate=false
dispatchThrottlingOnNonBacklogConsumerEnabled=true
dispatchThrottlingForFilteredEntriesEnabled=false

Secondary configs that could be related to throttling behavior:
dispatcherMaxReadBatchSize
avgMessagesPerEntry

Pulsar-admin brokers update-dynamic-config --config dispatcherMaxReadBatchSize —value 100

Some references regarding the above configs:
apache#5710
apache#11325
apache#2977
apache#754
apache#4273
apache#5804
apache#12294
apache#17686

Are you willing to submit a PR?

• I'm willing to submit a PR!